In recent years, the display technology has been developed rapidly, and especially the organic electroluminescent device (OLED) display technology has been developed rapidly. Currently, there are mainly two kinds of technologies for colorizing large-sized white organic electroluminescent devices (WOLEDs), one of which is to form a display panel by directly manufacturing color filter patterns on a second substrate (COA, color filter on array), and the other of which is to form a display panel by assembling a first substrate and a second substrate, and providing spacers arranged spaced at certain intervals between the first substrate and the second substrate, wherein the spacers are used to support the first substrate and the second substrate.
As shown in FIG. 1, for a display panel consisting of a second substrate 102 and a first substrate 101, the first substrate 101 includes black matrixes 108, color filter patterns 109 of various colors provided above the black matrixes 108, and a planarization layer 110 provided above the black matrixes 108 and the color filter patterns 109 of various colors; a drain of a thin film transistor 103 on the second substrate 102 is electrically connected to an anode layer 104 of an organic electroluminescent device, the anode layer 104 is provided at one side close to the second substrate 102, a cathode layer 106 of the organic electroluminescent device is provided at one side away from the second substrate 102, a light emitting layer 105 is provided between the anode layer 104 and the cathode layer 106, and a plurality of organic electroluminescent devices are provide on the second substrate 102, the anode layers 104 of the organic electroluminescent devices are controlled by different thin film transistors 103 respectively, all of the cathode layers 106 are connected together, spacers 107 supports the first substrate 101 and the second substrate 102 therebetween, at this time, light emitted from the organic electroluminescent devices transmits the cathode layer 106, that is to say, the organic electroluminescent device is of a top-emitting type, the cathode layer 106 is commonly made of conductive material such as silver (Ag) and aluminium (Al), light transmission of which is low, thus it is required to select very thin conductive material so that light may transmit. It should be noted that, after the first substrate 101 and the second substrate 102 are manufactured separately, the first substrate 101 and the second substrate 102 are assembled to form a display panel, wherein the spacers 106 may formed on the first substrate 101 or on the second substrate 102.
The inventor finds that, in the organic electroluminescent device of top-emitting type adopted in the above display panel, the cathode layer 106 is thin due to requirement on transmittance, resulting in the fact that the cathode layer 106 has large resistance, and poor conductivity, therefore the light emitting performance of the organic electroluminescent device is poor, and the display effect is nonuniform.